Figure 3
Effect of norUDCA, TnorUDCA, GUDC, and UDCA on β1 integrin activation. Rat livers were perfused with (a) norUDCA, (b) TnorUDCA, (c) GUDC, and (d) UDCA for up to 60 min with the concentrations indicated. Liver samples were immunostained for the active conformation of β1 integrin (red). The scale bar corresponds to 50 µm. Representative pictures of at least three independent experiments are depicted. To enhance visibility of the images, the white point of all channels in the RGB color space was reduced from the standard value of 255 to a value of 128. For each image, pixel intensities are indicated as average ± SEM. NorUDCA and TnorUDCA triggered activation of the β1 integrin subunit within 15 min, with stronger effects observed with norUDCA. In contrast, equimolar concentrations of UDCA and GUDC were ineffective. Like TUDC (Fig. 4)5, norUDCA-induced β1 integrin activation occurred primarily in the intracellular compartment of hepatocytes. (e) Staining of total α5β1 integrin (red) and filamentous actin labeled with FITC-coupled phalloidin (green) at t = 0 min and t = 15 min after perfusion with norUDCA, TUDC, GUDC, and UDCA.
